Ordinary toothbrushes are configured in such a way that a head member with bristles is straight to a handle member.
When brushing teeth with such a straight-type toothbrush, the toothbrush is moved in a left and right direction, so that alien substances between teeth are not completely eliminated, and enamel is likely to be damaged, which may cause dental disease.
In order to prevent the above problem, a method of brushing teeth up and down from a gum to ends of teeth is recommended. In case of the straight-type toothbrush, however, since it is difficult to move the toothbrush up and down, a user brushes his or her teeth in a left and right direction by habit. Therefore, there is a problem in that it is not possible to prevent the enamel from being damaged.
In addition, there is another problem in that even though a user brushes his or her teeth up and down with the straight-type toothbrush, the carpal tunnel of the wrist is frequently moved to easily damage the carpal tunnel.
In order to easily brush teeth up and down, a T-shape toothbrush is disclosed in Korean Utility Model Registration No. 0266621.
In case of the conventional T-shape toothbrush, there is a problem in that brushing teeth up and down (when brushing front teeth and canine teeth) is easy, but brushing teeth from side to side (when brushing rear teeth) is not easy.
In addition, the front teeth of the lower jaw are generally configured to protrude to the top. In case of the conventional T-shape toothbrush, since bristles 121a are arranged in parallel with the front teeth, as shown in FIG. 1, the lower portion of the front teeth T′ of the lower jaw do not come into contact with the bristles 121a. 
At this time, in case where a handle member 110 is pulled toward the direction of the jaw in order to brush the lower portion of the front teeth T′, the handle member 110 trips against the jaw, and thus the lower portion of the front teeth T′ of the lower jaw do not come into contact with the bristles 121a. Therefore, since dental plaque gets buildup at the lower portion of the front teeth T′ of the lower jaw, a user frequently flosses his or her teeth, thereby prolonging brushing time.